This BBC/BBC America miniseries, filmed in Toronto, was broadcast on 2 November 2006 on BBC1 in the UK, and in the US in February 2007.
I have to admit that although the episodes have been in my possession in a digital form for a while, I never got past episode one because I didn't have any subtitles. It's not too hard to follow most of the time but with the political stuff, I'm lost. Luckily, I found it in Belfast last week so I now have the episodes on DVD -with- subtitles and I quite liked the series. Thought I knew who the mole was and it turned out to be completely different. Love it!